Novel ambient temperature curable two-component waterborne silicone-acrylic coatings

Waterborne coatings are composed of resins containing hydrophilic functional groups. These groups usually remain in the coating film and can adversely affect film properties such as weatherability and resistance to water and alkali. We have developed a novel ambient temperature curable waterborne two-component system, in which the hydrophilic functional groups are consumed by the crosslinking reaction. The new coating system consists of a waterborne acrylic resin containing both tert-amino and carboxylic acid groups and a hardener containing both epoxy and alkoxysilyl groups. The waterborne silicone acrylic coatings provide superior film properties even if the acrylic resin has relatively low functional group content. In this paper we describe the crosslinking reaction mechanism and film properties using some acrylic resin types and paint formulations as examples. Presented at the 24th Annual Waterborne, High-Solids, and Powder Coatings Symposium, on February 5–7, 1997, in New Orleans, LA. 1-3 Takasago, Takaishi-shi, Osaka, Japan.